Sales of new vehicles by General Motors Co. and Fiat Chrysler Automobiles were down 10% year-over-year in the period from July through September, as dealers struggled to get new models on their lots due to the two-month shutdowns of auto plants.

Going into the fourth quarter of the year, a major selling time for automakers, industry experts are watching historically low inventory levels closely to see how they affect consumer purchasing decisions as they return to new-car showrooms in increasing numbers. Relatively few 2021 vehicles are on dealer lots even though it’s October.